Relógios biológicos e padrões de alimentação em camundongos normais e com sobrepeso

• Ano de defesa: 2011
• Autor(a) principal: Souza, Priscila Queiroz Pires de
• Orientador(a): Moura, Anibal Sanchez
• Banca de defesa: Filgueiras, Cláudio Carneiro , Santos, Penha Cristina Barradas Daltro , Menezes, João Ricardo Lacerda de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Fisiopatologia Clínica e Experimental
• Departamento: Centro Biomédico::Faculdade de Ciências Médicas
• País: BR
• Palavras-chave em Português: Ritmo circadiano; Programação metabólica; Hipotálamo; Obesidade; Hiperfagia; Comportamento alimentar; CLOCK; BMAL1; Per1; Per2; Per3; Cry1; Cry2; Nutrição
• Palavras-chave em Inglês: Circadian rhythm; Metabolic programming; Hypothalamus; Obesity; Hyperphagia; Feeding behavior; CLOCK; BMAL1; Per1; Per2; Per3; Cry1; Cry2; Nutrition
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::FISIOLOGIA::FISIOLOGIA DE ORGAOS E SISTEMAS
• Link de acesso: http://www.bdtd.uerj.br/handle/1/12731

The healthy interaction between the subject and the environment depends on the alignment between the physiological dynamics of the first one and the periodical movements of nature. The interaction between these rhythms in turn is based on the derivation and evolution process. The involvement of such an alignment is a risk to the survival of species. In this context the bodies line up their physiological rhythms to different external cycles. Thus, endogenous cycles are coordinated by biological clocks which determine in our organism specific rhythms in phase with the nature, such as Circadian Rhythms (CR) whose period is close to 24 hours. The body weight, the food intake and the energy consumption are processes characterized by the CR and the obesity is associated with a different timing of this process. The CR modulation is a result of the formulation of clock-gens CLOCK and BMAL1 who form an heterodimer responsible for the gene transcription of Per1, Per2, Per3, Cry1 e Cry2. The proteins encoded by these genes, once synthesized, form dimers (PER-CRY) in the cytoplasm that, depending on a given concentration, return to the core blocking the action of the CLOCK/BMAL1 heterodimer in the transcription of its own genes, thus forming a negative feedback loop of transcription and translation. These genes secure the periodicity and are significantly expressed in the hypothalamus suprachiasmatic nucleus. In order to study this process in regular, hyper-fed, hungry and satiated mice, we used a registration method of feeding behavior based on the sound produced by animal feeding and the relation between the metabolic states with the expression CLOCK, BMAL1, Per1, Per2, Per3, as well as the Cry1 and Cry2 proteins in the SCN, by analysis of images obtained in confocal microscopy. Control Swiss mice in state of hunger/ satiated were compared to hyper-fed animals in the same conditions. None of them showed difference in the CLOCK and BMAL1 contents, showing a potential capacity to modulate the biological rhythms. However, the Per1, Per2, Per3 and Cry1 proteins showed a minor expression in the CS group and a significant difference when compared to the CF group (P<0,05). This difference can t be found in the HF and HS groups. The results of the studies indicated that the endogenous and exogenous changes, reflected by the hyperphagic behavior observed in hyper-fed mice, may be due to a defect in the mechanism of negative feedback associated to the Cry-Per dimer, which has abolished the blocking mechanism of Per1 Per2, Per3 and Cry1 by the CLOCK-BMAL1 heterodimer.